What is ONVIF?
ONVIF: The original is the Open Network Video Interface forum , that is, the open web Interface forums, is an axis, Bosch, Sony and other three companies in 2008 jointly established an international open-type Network Video product standard network interface Development Forum, later by this Technology Development Forum jointly developed open industry standard, use the forum's capital letter name, namely ONVIF Network Video standard specification, customary abbreviation is: onvif agreement.
The importance of Onvif
The advent of the ONVIF Network Video protocol solves the problem that different kinds of equipment developed by various vendors can not be fused, and provides a unified network video development standard, that is, the integration between different products can be realized by onvif this standardized platform finally. In the security monitoring industry, the ONVIF protocol will be the first choice in the field of network video over a long period of time.
1, Synergy: Different manufacturers provide products, can be through a unified "language" to communicate. Facilitates the integration of the system.
2. Flexibility: End users and integrated users do not need to be constrained by the inherent solutions of certain devices. Greatly reduces the development cost.
3, Quality assurance: The continuous expansion of the norms will be guided by the market, in accordance with the norms and also meet the needs of mainstream users.
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The ONVIF standard defines a common protocol for the exchange of information between network video devices , including device search , real-time video , audio , and meta-data and control information and so on. The wide range of possibilities available to network video products makes it easy for end users, integrators, consultants and manufacturers to benefit from cost-effective, flexible solutions, market expansion opportunities, and lower risk.
The ONVIF specification describes the models, interfaces, data types, and patterns of data interaction for network video. and re-used some existing standards, such as the WS-Series standards.
The goal of the ONVIF specification is to implement a network Video framework protocol that allows for complete interoperability of network video products produced by different manufacturers, including recording front end, video recording equipment, etc.
The interfaces defined in the Device Management and Control section of the ONVIF specification are provided as Web services.
The ONVIF specification covers the full definition of XML and WSDL. Each terminal device supporting the ONVIF specification must provide a Web Service corresponding to the function. The service side interacts with the client's data using the SOAP protocol.
Other parts of the onvif, such as audio and video streams, are performed through RTP/RTSP.
Due to the use of Wsdl+xml mode, the subsequent extension of the ONVIF specification will not encounter too much trouble. The very strong extensibility of XML and the ease of development of the SOAP protocol will attract more people to focus on and use the ONVIF specification.
Onvif's organization is growing, occupying an absolute advantage over the PSIA,HDCCTV in the same field. Member companies are not lack of well-known domestic and foreign equipment manufacturers and integrators. A set of norms, the life cycle of the agreement, and market share is closely related. and the development of onvif norm is to be driven by the market, by the user to enrich. Each member enterprise has the right to strengthen and expand the onvif norms. The areas covered by the ONVIF specification will continue to grow. At present, the related content of access control system will be included in the ONVIF specification.
In the rapid development of security, monitoring systems today, the efficiency and quality of the lead brought about by the value of self-evident. The ONVIF protocol provides such potential.
ONVIF the implementation mechanism of the norm
1. Web Service
2. Wsdl
3. Soap
Web Service is a network-based, distributed, modular component that performs specific tasks. Web Service primarily leverages HTTP and SOAP protocols to make data transport over the Web. Web users can invoke remote objects using SOAP and HTTP through the Web call method.
The client describes the document according to the WSDL and generates a SOAP request message that is embedded in an HTTP POST request and sent to the Web server on which the Web Services resides. The Web services request processor resolves the received SOAP request and invokes the appropriate Web services. The corresponding SOAP reply is then generated. After the WEB server receives a SOAP response, it sends the message back to the client in the form of an HTTP reply.
WSDL is the abbreviation for the Web Services Description Language (Web Service Description Language). is an XML language that describes Web services and describes how to communicate with Web services, providing users with detailed interface instructions.
SOAP is an abbreviation for simple Object Access protocol. is an XML-based protocol. A SOAP message is a plain XML document that contains the following elements:
Required Envelope element to identify this XML document as a SOAP message
Optional header element with header information
Required Body element, including all call and response information
An optional Fault element that provides information about the error that occurred while processing this message
In a SOAP request sent to a Web service, the fields in the body element should conform to the data type in the WSDL. In the process of building soap, this correspondence must be fetched and mapped from the WSDL file. However, such a correspondence process will be full of repeatability and mechanical, in order to avoid unnecessary artificial errors and save development time, a compile tool called gSOAP came into being.
gSOAP uses compiler technology to provide a transparent set of soap APIs and hides content related to the development-agnostic SOAP implementation details to the user. The development of Web service is minimized by parsing the WSDL file into a C + + file.
Web Service Development process
WEB Service and video surveillance
The ONVIF specification introduces the concept of Web service to video surveillance. The actual function of the device is abstracted for the service of the Web service, the control unit of the video monitoring system appears as the client, and the control operation is done through the Web request.
What can Web service bring to a video surveillance system?
Device independence, any one device access system, will not affect other systems.
The independence of the device, each device is only responsible for connecting to the received request to make feedback, even do not need to know the existence of the control side.
The centralization of management, all the controls are initiated by the client.
What does the ONVIF specification bring to a video surveillance system?
An interface that abstracts functionality. Unifies the configuration of the device and how it operates.
The control side does not care about the model of the device, but the web Service provided by the device
The behavior outside the scope of the Web service in the video system is regulated.
The ONVIF provides WSDL for each module and has a very efficient development approach.
ONVIF specification of the content directory
01. Equipment Discovery
02. Equipment Management
03, equipment input and output services
04. Image Configuration
05. Media Configuration
06. Real-Time Streaming media
07. Receive-Side configuration
08. Display Service
09. Event Handling
10. PTZ Control
11. Other functions
based on ONVIF development of the normative project
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Camera Standard ONVIF---Open Network Video Interface Forum ONVIF introduction